RESUMEN
<p><b>OBJECTIVE</b>To investigate the expression of indoleamine 2, 3-dioxygenase (IDO) in breast cancer and its correlation with clinicopathologic factors and prognosis.</p><p><b>METHODS</b>The expression of IDO, CD31, CD105 proteins in 40 specimens of breast cancer were assessed by immunohistochemistry.</p><p><b>RESULTS</b>The overexpression rate of IDO in breast cancer was 67.5% (27/40), and expression of IDO was closely associated with clinical stage and lymph nodes metastasis. The disease-free survival rate in patients with IDO overexpression was not significantly lower than that in patients with negative or low expression of IDO (P > 0.05). Moreover, the expression of IDO was positively correlated with CD105-labeled microvessel density (r = 0.659, P < 0.05).</p><p><b>CONCLUSIONS</b>Expression of IDO is associated with clinical stage and lymph nodes metastasis, and microvessel densitty. IDO expression may promote the growth and metastasis of breast cancer, probably via the increased agiogenesis. A larger sample study is needed to verify whether the prognosis of beast cancer is significantly correlated with IDO expression.</p>